The impact of stress on feedback and error processing during behavioral adaptation.

Stress is known to influence learning in a complex fashion. The present study aimed to examine, in how far feedback-based behavioral adaptation and electrophysiological correlates of error and feedback processing during this process are altered after acute stress. To this end, a learning task involving conditions with contingent and non-contingent monetary feedback was applied to 40 healthy young men (two groups of 20 each). The participants of one group were stressed using the socially evaluated cold pressor test. A second group of participants underwent a control procedure before the task was administered and brain activity was assessed by means of electroencephalography. The analysis focused on the feedback-related negativity (FRN) and the error-related negativity (ERN). Stressed participants did not differ from controls in learning performance. They showed, however, an elevated FRN amplitude difference between punishment and reward compared to controls. Moreover, stressed but not control participants' FRN amplitudes reflected feedback contingency after learning and thus an outcome prediction error. For response-locked potentials, no significant group differences were found. These results indicate that stress leads to a stronger recruitment of the so-called reward system in the processing of performance feedback during feedback-based behavioral adaptation.